We will develop a practical and efficient laser ablation tool for removing superficial caries and for minor sculpting of enamel and dentin. For this specific application, we believe that our proposed tool matches the high- speed drill. The ablation tool will combine a pulsed laser (e.g., Nd:YAG) and a miniature dye dispenser (Microjet). The Microjet and laser optics will be combined in a compact hand piece, allowing the dentist to dispense dye- microdrops interactively, between laser pulses. The dye governs the absorption of laser energy, giving (i) maximal absorption at the dyed tooth surface (for efficient and controlled ablation) and (ii) minimum laser penetration into the tooth. In Phase I we showed that dye-assisted laser ablation is feasible; in Phase II we will establish (i) what laser and dye-spot parameters give the best ablation rates with the minimum tissue damage, and (ii) how to design and build a jet+laser handpiece that will be practical for use in the dental office. The final goal of Phase II is to produce a working prototype that can be fitted to new or existing lasers and will be suitable for use in Phase III clinical trials. PROPOSED COMMERCIAL APPLICATION: We believe that dye-assisted lasers can ablate hard and soft dental tissues and dental restorative materials in a safe, practical, and low-trauma manner. There are over 140,000 dentists who could potentially use the system that we are developing.